The upcoming discussion will update you about the difference between external and internal respiration in animals.
Difference # External Respiration:
1. It is a physical process in which oxygen (O2) is absorbed and carbon dioxide (CO2) is given out.
2. Enzymes do not play any role in the process.
3. Restricted to respiratory organs only.
4. Respiratory structures are body surface, gills, lungs, etc. exposed to the surroundings.
5. Sites of gaseous exchange—moist respiratory surfaces; inflow of O2 and outflow of CO2 occurs through plasma membrane by passive diffusion.
6. Partial pressure of O2 in the surroundings determines the rate of O2 diffusion.
Difference # Internal Respiration:
1. It is a chemical reaction in which oxygen (O2) combines with carbohydrates, fatty acids and amino acids (biological oxidation), producing carbon dioxide (CO2), water and energy.
2. The whole process is enzyme controlled.
3. It takes place in all living cells.
4. Respiration occurs within the cells.
5. Sites of reaction— cystosole of the cell and mitochondria; O2 and CO2move in and out of the cell through plasma membrane by passive diffusion.
6. Pressures of O2 and CO2 inside the cell and interstitial fluid determine the rate of diffusion of the gases and CO2 concentration in blood influences the release of O2 from oxyhaemoglobin (HbO2).